Anterior ischaemic optic neuropathy associated with central retinal vein occlusion

Purpose To report the unusual association between non-arteritic anterior ischaemic optic neuropathy (NAION) and non-ischaemic central retinal vein occlusion (CRVO) in two patients. Methods Case reports are presented. Results Non-ischaemic CRVO was manifested by dilated, tortuous retinal veins with flame-shape retinal haemorrhages. Fluorescein angiography showed prolonged arteriovenous transit time and normal retinal capillary perfusion without macular oedema. The presence of colour vision abnormalities, relative afferent pupillary defects, pale disc swelling and visual field deficits indicated that the visual loss was attributable entirely to NAION. Laboratory investigations disclosed impaired fibrinolytic function in case 1 and the presence of antiphospholipid antibodies in case 2. Conclusions Compression of the central retinal vein by the swollen optic nerve could have predisposed to CRVO. The presence of thrombophilic abnormalities may have contributed to the concomitant occlusion of posterior ciliary arteries and central retinal vein. Ischaemic optic neuropathy needs to be considered in patients with CRVO when the visual acuity is not consistent with the retinal pathology.